Thin and thick disk kinematics with RAVE and the solar motion
Stefano Pasetto (University of Heidelberg)

I present some preliminary results on the kinematic analysis of the Galactic thin and thick disk based on RAdial Velocity Experiment (RAVE). Thin and thick disk components of the Milky Way, considered as distinct entities, are disentangled from a two-component mixture with a method based on matrix decomposition. The prospects and limitations of this method are currently under investigation and explored with and without the use of photometric distances and proper motions. We deduced the components of the solar motion relative to the Local Standard of Rest in the radial and vertical direction as well as the components of the velocity dispersion tensor for the thin and thick disk in the meridional plane.

Dihadron fragmentation functions describe the probability that a quark fragments into two hadrons plus other undetected hadrons. In particular, the so-called interference fragmentation functions describe the azimuthal asymmetry of the dihadron distribution when the quark is transversely polarized. They can be used as tools to probe the quark transversity distribution in the nucleon. We will present recent studies on unpolarized and polarized dihadron fragmentation functions. We will then discuss their relevance in the observations of the transversity parton distribution function based on an analysis of pion-pair production in deep inelastic scattering off transversely polarized targets.

The existence of non-baryonic Dark Matter (DM) is well established by cosmological and astrophysical probes. However, despite the great experimental efort over many years, its nature still remains elusive. Elucidating the long-standing puzzle of the nature of dark matter constitutes one of the most important challenges of modern cosmology and particle physics.

We suggest that the same non-abelian discrete flavor symmetry which accounts for the observed pattern of neutrino oscillations, spontaneously breaks to a Z2 subgroup which renders DM stable. The simplest scheme leads to a scalar doublet DM potentially detectable in nuclear recoil experiments, inverse neutrino mass hierarchy, hence a neutrinoless double beta decay rate accessible to upcoming searches, while the reactor angle is zero, gives no CP violation in neutrino oscillations.

The origin of the long-range rapidity correlations between pairs of charged particles, produced in the collisions of hadrons at high energy (the CMS ridge effect) can be attributed to quantum entanglement. We argue that the observed correlations can be understood in terms of non-local interactions of path-dependent phase factors that include the effect of the primordial separation of a charged particle from its partner with the opposite polarity. Phase factors also enter the definition of the transverse-momentum dependent parton densities used in the factorization formulas for semi-inclusive processes in QCD.

Astrophysical and cosmological observations do not require the dark matter particles to be absolutely stable. If they are indeed unstable, their decay into Standard Model particles might occur at a sufficiently large rate to allow the indirect detection of dark matter through an anomalous contribution to the high energy cosmic ray fluxes. In this talk we discuss the implications of the excess in the total electron plus positron flux and the positron fraction recently reported by the Fermi and PAMELA collaborations, respectively, for the scenario of decaying dark matter. We also discuss the constraints on this scenario from measurements of other cosmic ray species and the predictions for the diffuse gamma ray flux.

Cygnus OB2 is the most massive young stellar association within 2kpc, containing at least 65 O-type stars and a total mass of ~30,000 Msun. Its proximity provides a unique glimpse into star formation at the largest of scales: the extreme physical conditions induced by the proximity of thousands of massive stars, and the large spatial scales under which the star formation process takes place. It represents a vital stepping stone between studies of nearby regions such as Orion and the distant super-star clusters that dominate starburst galaxies.

I will present results from the recent Chandra Legacy Survey of Cygnus OB2, which has produced a catalog of ~10,000 young stars with well-defined completeness limits. Results from these and other multi-wavelength observations are helping us understand how the fundamental products of star formation vary in these massive regions. I will also discuss a follow-up radial velocity survey of the association that will not only reveal the current dynamical state of the association, but also probe the formation and eventual dissolution of such massive star forming regions.

We present a simple formula for the total cross section sigma^ of neutral- and charged-current deep-inelastic scattering of ultrahigh-energy neutrinos on isoscalar nuclear targets, which is proportional to the structure function F_2^(M_V^2/s, M_V^2), where M_V is the intermediate-boson mass and s is the square of the center-of-mass energy. The coefficient in the front of F_2^(x, Q^2) depends on the asymptotic low-x behavior of F_2^. It contains an additional ln(s) term if F_2^ scales with a power of ln(1/x). Hence, an asymptotic low-x behavior F_2^ propto ln^2(1/x), which is frequently assumed in the literature, already leads to a violation of the Froissart bound on sigma^.

Usually, photons are described by plane waves with a definite 4-momentum. In addition to plane-wave photons, "twisted photons" have recently entered the field of modern laser optics; these are coherent superpositions of plane waves with a defined projection hbar*m of the orbital angular momentum onto the propagation axis, where m is integer. We show that it is possible to produce high-energy twisted photons by Compton backscattering of twisted laser photons off ultra-relativistic electrons. Such photons may be of interest for experiments related to the excitation and disintegration of atoms and nuclei, and for studying the photo-effect and pair production off nuclei in previously unexplored experimental regimes.

Clumping and Porosity in Massive Star Winds, and How They Affect the Observed X-ray Emission
David Cohen (Department of Physics and Astronomy, Swarthmore College, Pennsylvania, USA)

There is now a widespread realization that all hot, massive star winds are clumpy -- that is, they are characterized by density inhomogeneities. Clumping affects all density-squared diagnostics, including H-alpha and IR/radio free-free, and recent analyses of massive star winds that account for clumping have led to a downward revision in the observationally inferred mass-loss rates of these stars. The density-squared effect does not depend at all on the size scale of the clumps, only on their density contrast, as long as the clumps are optically thin. But another effect -- porosity -- may be important in clumped winds if the individual clumps are optically thick. Porosity enhances the escape of X-ray photons through the low-density interclump channels, and has been invoked as an explanation for the observed low level of X-ray absorption in O star winds. However, in this talk I will show that the observed X-ray spectra -- both broadband SEDs and the profiles of individual lines -- are consistent with the observed H-alpha emission in the context of modestly lower mass-loss rates, without having to invoke any porosity effects. And furthermore, I will show how porosity due to flattened clumps imparts a characteristic emission bump at the line-center of X-ray emission lines, for which there is no evidence in the data

After fifty years from their discovery, the nature, the origin, the propagation to Earth of the Ultra High Energy Cosmic Rays (cosmic particles with energy in excess of 5x10^19 eV) lie still in the dark. In my talk I will first discuss the science case at the base of the exploration of the Ultra High Energy Universe, presenting all findings and contradictions of the current observational scenario. I will then present the new experimental efforts in the field, focusing on the science requirements, the expected performances and the instrumental aspects of the challenging JEM-EUSO mission: the Extreme Universe Space Observatory onboard the JEM module of the International Space Station.

Further generalization of the concept of generalized parton distributions (GPDs) leads to introduction of baryon to meson transition distribution amplitudes (TDAs), non-diagonal matrix elements of nonlocal three quark operators between a nucleon and a meson states.

These non-perturbative objects appear as a building block in the collinear factorized description of amplitudes for a class of hard exclusive reactions prominent examples being hard exclusive pion electroproduction off a nucleon in the backward region and baryon-antibaryon annihilation into a pion and a lepton pair in the forward direction.

We discuss general properties of baryon to meson TDAs following from the underlying symmetries of QCD. We generalize the notion of double distributions introduced in the context of GPDs and construct the spectral representation for baryon to meson TDAs in terms of quadruple distributions. Using chiral symmetry together with the crossing relation between $\pi N$ TDAs and generalized distribution amplitudes ($\pi N$ GDAs) we establish threshold soft pion theorem for $\pi N$ TDAs which determines the magnitude of $\pi N$ TDAs at a low normalization point. We suggest a factorized Ansatz for the corresponding quadruple distributions with input from the soft pion theorem.

Finally, we present estimates of the cross section and of single transverse spin asymmetry for backward pion electroproduction and discuss perspectives of experimental measurements.

The effect of the small-t properties of hadronic scattering on the determination of rho(s,t)
Oleg Selyugin (JINR, Dubna)

The existing experimental data are examined under various assumptions about the structure of the scattering amplitude of the proton-proton and proton-antiproton elastic scattering at high energy to obtain the value of rho(s,t), the ratio of the real to imaginary part of the scattering amplitude in the Coulomb-hadron interference region. It is shown that the deviation of rho(s,t) obtained from the experimental data of the proton-antiproton scattering at 3.8 < p_L <6.0 GeV/c from the dispersion analysis is critical under all examined assumptions. The experimental data are analyzed to obtain rho(s,t) for pp and p\bar

elastic scattering. All known effects are taken carefully into account: the Coulomb interference, ii) spin effects, and (briefly) oscillations in the small t-region. While the analysis is waiting for better high energy data, the result for p\bar

When a charged particle moves nearby a spatially inhomogeneous condensed medium or inside it, different types of radiation may arise: Cherenkov radiation (ChR), Transition radiation (TR), Diffraction radiation (DR), Smith-Purcell radiation (SPR) etc. Along with transverse waves of radiation, the charged particle may also generate longitudinal waves. We show that all these phenomena may be described via quite simple and universal approach, where the source of the field is the polarization current density induced inside the medium by external field of the particle, that is direct proof of the physical equivalence of all these radiation processes. Solution for the problem of emission of a particle passing through a cylindrical channel in a screen of arbitrary permittivity $\epsilon (\omega) = \epsilon^ + i \epsilon^$ is found with the use of this method. Depending on geometry, the formula for radiated energy obtained describes different types of polarization radiation: DR, TR and ChR. The problem of SPR generated when the particle moves nearby a set of thin rectangular strips (grating) is solved for the arbitrary value of the grating's permittivity. An exact solution of Maxwell equations for the fields of polarization current density suitable at the arbitrary distances (including the so-called pre-wave zone) is presented. This solution is shown to describe transverse fields of radiation and the longitudinal fields connected with the zeros of permittivity.

Overview of the 3.6m IDOT Project and some results on the unusual
hydrogen-rich supernovae
Brijesh Kumar (ARIES; Aryabhatta Research Institute of Observational Sciences, India)

The Indo-Belgian Devasthal Optical Telescope (IDOT) project aims at setting a 3.6m aperture modern telescope at Devasthal in the central Himalayas. Devasthal is a low-wind astronomical site with a median seeing of about one arcsec and it also has added advantage of being located in the middle of crucial longitudinal gap between observing facilities in Australia at East and the Canary Islands at West. The telescope is under construction in Belgium and it is due for installation by the end of the year 2012. A short overview and the current status of the 3.6m IDOT project will be presented at the beginning of the talk, while the later part will be focused on the hydrogen-rich core-collapse supernovae (SNe). Study of SNe is used to probe the star formation processes, galactic chemical evolution and constrain the stellar evolution models. Theoretically, the explosion mechanism for core-collapse SNe is similar, though they differ greatly in the observed energetics and the chemical yields. A number of SNe have been discovered recently showing unusual characteristics that do not match the traditional classification schemes. An observational study of two nearby unusual SNe 2008gz and 2008in will be presented and discussed.